function sys=obv(t,x,U1,U2,e1,e2)
sys=zeros(5,1);

k11=25;k12=33;
k21=25;k22=25;k23=-1;
lamb=2;

sys(1)=x(2)+k11*abs(e1)^0.5*sign(e1);
sys(2)=U1+k12*sign(e1);
sys(3)=x(4)+k21*abs(e2)^(2/3)*sign(e2);
sys(4)=x(5)+U2+k22*abs(e2)^(1/3)*sign(e2);
sys(5)=k23*sign(e2);
